There are known many diseases caused by circadian rhythm disorders. Various types of circadian rhythm regulatory agents have been proposed to alleviate these diseases.
For example, a circadian rhythm regulatory agent containing an endocrine hormone, such as melatonin, is known. However, treatment with endocrine hormones has a safety problem on account of the risk of side effects so that a material with high safety has been sought for.
Sleep disorders which are now a social issue include circadian rhythm sleep disorders. To basically remedy circadian rhythm sleep disorders, a material that regulates the diurnal cycle has been demanded.
There are reports on circadian rhythm regulatory agents of food origin. For example, patent literature 1 below discloses a composition containing as an active ingredient cryptoxanthin extracted from satsuma orange (Citrus unshiu) and/or an ester thereof and having a circadian clock normalizing effect. Patent literature 2 below discloses a circadian rhythm normalizing composition having arachidonic acid-containing fat and oil as an active ingredient.
Synthetic alkylresorcinols and derivatives thereof and alkylresorcinol-containing extracts from the hull of cereal grains, such as wheat and rye, or the shell of nuts, such as cashew nuts, are reported to have anti-obesity effect, antioxidant effect, anti-immune effect, and the like. However, it is unknown that alkylresorcinols exhibit circadian rhythm regulatory effects.
Alkylresorcinols are reported to be present in a wide range of plants as resorcinol-lipids that are natural, non-isoterpenoid phenolic, amphiphilic compounds (see non-patent literature 1 below). The non-patent literature 1 reports that the plants as a source of resorcinol lipids include those belonging to the families Anacardiaceae, Ginkgoaceae, Proteaceae, Myrsinaceae, Primulaceae, Myristicaceae, Iridaceae, Araceae, Artemisia of Compositae, Fabaceae, and Poaceae. With respect to the toxicity of alkylresorcinols, non-patent literature 2 below reports that no apparent toxicity is observed in oral administration to rats of 5 g/kg-b.w. of 4-alkylresorcinol having a saturated C15 alkyl group of cashew nut shell origin.